Recently, the needs of rapidly processing photographic materials are being great. In particular, systems of completely processing photographic materials exposed to X-rays within a period of 30 seconds have become popularized. In addition, the needs of reducing the amounts of the replenishers to be added to photographic processing systems are also being great. Accordingly, the tendency toward the reduction in the amount of silver to be coated on photographic materials is now the mainstream in this technical field. However, when such photographic materials having reduced silver coated thereon are processed with an automatic developing machine, the light-shieldability of infrared sensors set in the conveying system including the machine is lowered so that the detection of the position of the photographic material being processed often becomes impossible thereby causing a mechanical failure in conveying the material being processed.
In JP-A-62-299959 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), disclosed is a method of adding an infrared-absorbing dye of a certain kind to a photographic material so as to overcome the mechanical failure in detecting the photographic material being processed. However, this method has various problems in that it needs the adsorption of the dye onto silver halide grains of a photographic material, that the dye adsorbed onto the grains brings about an additional load in the steps of processing the photographic material (especially in the fixation step), and that the coating of photographic emulsions on a support to prepare the photographic material is complicated. In addition, since the dye itself absorbs visible rays, it causes another problem with a black-and-white photographic material that gives a silver image to be viewed. In JP-A-63-131135, disclosed is a method of utilizing light-scattering grains such as silver halide grains in a photographic material so as to overcome the mechanical failure in detecting the photographic material being processed. However, since this method merely utilizes the refractive index of the photographic material containing the grains, it also has various problems in that the light-shielding effect of the material for sensors is insufficient and that, when the light-scattering grains are silver halide grains, they cause an additional load in the fixation of the photographic material. For these reasons, therefore, this method is not applicable to the technique of reducing the amounts of replenishers in rapid processing of photographic materials.
In JP-A-3-226736, disclosed is a method of adding dyes to photographic materials. However, this method is not satisfactory, since the photographic materials rapidly processed have inevitable residual color.
In JP-A-2-113239, JP-A-3-37271, JP-A-5-323550 and U.S. Pat. No. 2,639,282, disclosed are cyanine dye polymers to be added to photographic materials. However, these polymers are still unsatisfactory in that they are not photochemically inactive and that they cause residual color in the processed photographic materials containing them.